Discharge Performance of Li–O₂ Batteries Using a Multiscale Modeling Approach

Abstract

To study the discharge performance of Li-O 2 batteries, we propose a multiscale modeling framework that links models in an upscaling fashion from nanoscale to mesoscale and finally to device scale. We have effectively reconstructed the microstructures of a Li-O 2 air electrode in silico, conserving the porosity, surface-to-volume ratio, and pore size distribution of the real air electrode structure. The mechanism of rate-dependent morphology of Li 2 O 2 growth is incorporated into the mesoscale model. The correlation between the activesurface-to-volume ratio and averaged Li 2 O 2 concentration is derived to link different scales. The proposed approach's accuracy is first demonstrated by comparing the predicted discharge curves of Li-O 2 batteries with experimental results at the high current density. Next, the validated modeling approach effectively captures the significant improvement in discharge capacity due to the formation of Li 2 O 2 particles. Finally, it predicts the discharge capacities of Li-O 2 batteries with different air electrode microstructure designs and operating conditions.

Machine Learning Coupled Multi‐Scale Modeling for Redox Flow Batteries

“…The insert in Figure shows the pore‐scale modeling domain, in which the green block represents a pore structure of the porous electrode, the void space represents the buffer zone to reduce inlet/outlet boundary effects, and the green arrows represent the electrolyte flow direction. For pore‐scale fluid transport, the lattice Boltzmann equation (LBE) model has been applied for modeling VRFBs and other battery systems at the pore scale because of its simple wall boundary treatment method and high parallel computational efficiency . The LBE model is derived from the continuum Boltzmann Bhatnagar–Gross–Krook (BGK) equation .…”

“…A multi‐scale framework is a viable approach for indirectly passing information to a device‐scale model. For example, Bao et al . and Pan et al .…”

“…A multi-scale framework is a viable approach for indirectly passing information to a device-scale model. For example, Bao et al [36] and Pan et al [37] introduced an upscaling approach that connects the pore structure of the cathode and devicescale discharging performance of an LiO 2 battery and used the approach to optimize the design of the cathode pore structure. In our study, we applied a multi-scale framework coupled with ML to connect pore-scale modeling to device-scale estimation for a flow battery and used the approach to optimize the inlet flow rate.…”

Modeling Oxygen Gas Diffusion Electrodes for Various Technical Applications

“…Thus, these models do not combine reaction and transport in an electrochemically active three-dimensional electrode. Such a model has been presented by Bao et al [75] who used a multiscale approach for their study of the discharge performance of Li/O 2 batteries. After reconstruction of the oxygen electrode structure through a particle-packing method, the governing equations for oxygen reaction and diffusion in the porous electrode were numerically solved with an implicit finite volume scheme.…”

“…Bao et al [75] link a one-dimensional continuum model, that describes mass transfer and electrochemical reaction kinetics in a Li/O 2 battery, with a nano-scale model, that describes the development of the active surface area during discharge. In Fig.…”